bcipam brings up a really good point about cockpit length:

need to reach the bars and brakes while extended off the saddle
The way you'd test this is slighly stand up in the saddle feet at 3 & 9, and then move your torso back. You should ultimately be able to position yourself so that your chest is over your saddle and your butt is over the back tire. Sure, this is an extreme descending position but you never know when you might need it. This is a test is all.

My first bike was too long. I never realized how much too long it was until a friend stopped mid ride and moved my saddle as far forward as it would go. It was amazing how much difference even an inch or two made in shortening up the cockpit. It completely screwed up KOPS but I learned an important fit lesson.

I.